Almost all women get radiation therapy after lumpectomy to lower the risk of the cancer coming back (recurrence) in the breast area. Cancer coming back in the breast area is called locoregional recurrence.

Lumpectomy plus radiation has been shown to be as effective as mastectomy without radiation for many women. Radiation isn't routinely given after mastectomy, but many doctors believe that some women can lower their risk of locoregional recurrence more by getting radiation therapy after mastectomy.

Now, research suggests that women diagnosed with early-stage breast cancer that has spread to one or more underarm (axillary) lymph nodes can benefit from radiation therapy after mastectomy. The results were presented at the October 2011 annual meeting of the American Society for Radiation Oncology (ASTRO).

Researchers reviewed the records of 369 women diagnosed with early-stage breast cancer that had spread to one to three underarm lymph nodes. All the women had mastectomy; 98 had radiation therapy after mastectomy and 271 didn't. The researchers wanted to see if radiation therapy improved treatment outcomes. Half the women were followed for more than 5.5 years and the others were followed for shorter time periods.

During follow-up:

none of the 98 women who got radiation after mastectomy had a locoregional recurrence

24 (8.9%) of the 271 women who didn't get radiation after mastectomy had a locoregional recurrence

The results strongly suggest that radiation therapy after mastectomy may make sense for women who've been diagnosed with early-stage breast cancer that has spread to lymph nodes. Still, this was a retrospective study, which means that the results were based on treatment plans developed before the study was planned. Doctors are usually more confident in the results of a study where the treatment plans are part of the study design and randomly assigned to participants (prospective study) than a retrospective study. There are other prospective studies currently being done to see if radiation therapy makes sense after mastectomy and who would benefit from it.

If you've been diagnosed with breast cancer, you and your doctor will consider the specifics of the cancer, your unique situation, your surgical options, and your treatment options after surgery when creating your treatment plan. If you choose lumpectomy, it's very likely that radiation will be recommended after surgery. If you choose mastectomy, you might want to ask your doctor if you would benefit from radiation, especially if the cancer is large or has spread to more than one lymph node.

Using the most complete and accurate information, you and your doctor can develop a treatment plan that makes the most sense for you. You can learn more about radiation after breast cancer surgery in the Breastcancer.org Radiation Therapy section.